I Can`t Find Infested Pit Key Guardian

Im having trouble finding Infested Pit Key Guardian

 

I've seen them in two places.
The first is the place I would recommend: the Black Road. This is a good place to grind for them, and the main place people have seen them. They appear mainly on the northern part, near the Potion Making quest hut and the area between the mining town (not the abandoned mines, the one with the Blacksmith npc) and Ternaves.
The second is the road between east Nivla forest and Nemract. I actually saw both the Underworld Crypt guardian and the Infested Pit guardian in the same place once. I'm not sure exactly where the guardian spawns though, because I was just passing through.
Other than that, they should spawn in areas around the dungeon's level. These do seem to be the best places though.

 

Go near ternaves, if u see a pile of spiders, there's a guardian there.